Lamp



Feb. 3, 1931. l s. F. ARucKLE LAMP Filed March '7, 1925 I N V EN TOR. 5amue/ FArbuc/r/e ATTORNEY Patented Feb. 3, 1931 UNITED STATESPATENT OFFICE SAMUEL F. ARBUCKLE,.OF HIGHLAND PAR-K, MICHIGAN, ASSIGNOR TO MONOGRALVI LENS OOR-PORATIQN 0F NRVI YORK, N. Y., A COEPOLZATEON OF DELAXVABE LAM]? This invention relates to improvements in lamp construction, the invention having particular utility in connection with headlamps for automotive vehicles.

In electric lamp illumination for roads and similar passageways, as applied to moving vehicles, the problem has been to secure a close cooperation between the light source, reflecting surface and the refracting lens so that a light pattern is produced effective on the road to give a proper illumination over a wide area. both in front of the vehicle and to the sides thereof, without producing disadvantages and dangerous glare to an approaching observer. A solution of the problem of proper illumination involves careful consideration of the type of lens employed, the nature of the reflecting surface, the type of filament or filaments used, and the means of adjusting the filament both axially in relation to the reflector axis, and transversely in relation to said axis, such considerations being essential in order to secure illumination within legal requirements, and safe both to the driver of the vehicle and to pedestrians or approaching drivers in other vehicles.

Broadly stated therefore, the invention consists in a combination of specific types of lens, reflector, filament and adjusting means which gives effective and adequate illumination both near the automobile and at distances in front thereof and to the sides of the line of movement, as well as preventing both forward and back glare, the former arising from scattered upwardly extending light rays, and the latter from scattered rearwardly reflected reflection from mist particles and the like in front of the lamp.

In accordance with the nature of the invention, as above specified, it is an important object to provide means for securing effective cooperation between the various parts of the lamp provided with an electric light source, a paraboloid reflector anda refracting lens. Another object of the invention is to provide means for preventing secondary reflection from the interior of the lamp bulb, this See ondary reflection giving rise ordinarily to uncontrolled radiation, thus augmenting glare. Other objects contemplated in the invention are the provision of means for cutting off upwardly extending direct radiation; for

deflecting the light beams emerging from the reflector surface transversely, relative to the line of movement of the vehicle; for eliminating to a considerable extent the loose play of the lamp base within the socket; and in general providing means for maintaining the various individual elements of the lamp in ciosely united. relationship to each other irre spective of the amount of jar and vibration received by the movement of the vehicle.

With the above objects in mind, the invention is set forth in the following description as applied to an embodiment which may be preferred, and which is illustrated in the accompanying drawings, of which Figure 1 is 'a vertical longitudinal section through the headlamp;

Figure 2 is a detail of the lamp adjusting mechanism Figure 3 is a detail of means for preventing free movement of the socket;

Figure 4 is a detail showing means for preventing axial working of the adjusting screw;

Figure 5 is a detail of the adjusting screw head base; and

Fig. 6 is a detailed view of the lens used in connection with the headlamp.

Referring to Figure 1 of the drawing, there is shown in section, a type of headlamp wherein the casing 10 is of general cylindrical formation, one base 11 of which being flat and containing the socket 12 for the electric current plug 13 and screw mechanism for the adjustment of the lamp bulb and filaments, while the other base of the casing 10 is open and adapted to receive the paraboloid reflector 14 and the lens 15. Pivotally mounted by means of a stamped con nection 16 is a door unit 17, the same includingan annular rim 18 provided with an inturned flange 19 as shown, a thread pin 20 and a knurled screw nut 21 forming a looking means for the door in conjunction with the resilient plate 22. The plate 22 is preferably formed with a bifurcated end, the terminals 23 of which are outturned so that when the screw 21 is tightened, the terminals 23 are engaged and the door prevented from openin The reflector 14 is constructed with a radially extending outer flange adapted to contact with an inner projecting flange 31 formed on the edge of the casing cylinder 10. Intermediate the flange 30, cooperatively engaging the flange 31 of the casing and the edge of the reflector, is an annular groove 32 adapted to retain a flexible cord 33, the same forming a cushion intermediate the lens 15 and the reflector. With the reflector 15 in position, the cord contacts against the outer periphery thereof and the inner end of the flange 19 engages an annular shoulder 34 formed by molding the lens with a peripheral depression. This construction holds the lens securely in place from lateral movement, and by means of the cord 33 in conjunction with the rim of the door maintains the lens solidly in position relative to the axis of the lamp.

The lens, as indicated in Figure 6, is formed with vertical corrugations which serve to deflect the light transmitted there through. Preferably, the corrugations are in three zones, a central zone in which the thickness of the corrugations is reh ively small, and side Zones in which the thickness of the corrugations is relatively large, this construction bringing about a wider deflection of the light rays passing through the outer zones than that passing through the central zone and securing wide spread beam of maximum intensity in front of the lamp and of diminished intensity to the sides, the whole being wide spread and affording excellent illumination on the road and on the sides of the road.

A portion of the reflector adjacent the axis thereof is cut away to form an aperture, portions of the edge of which are rearwardly turned and curved, as indicated at 35 of Figure 1 and Figure 3. As more clearly brought out in Figure 3, the edge portions 35 of the reflector may be three in number with intervening spaces between so as to perniit frictional contact of a coil spring 36 with the socket 40 of the lamp, as will be brought out more fully hereinafter.

The socket 40 is positioned within the open versee central aperture of the reflector and is fre to move therein in an axial direction. Also the socket l0, since the inner surfaces of the hook members 35 are curved, and since the rea of contact between the hooks and the socket is small, has a degree of pivotal moveincnt in relation to the reflector hooks 35, permitting adjustment of the bulb within the reflector, and consequently of the lamp fllament as will be subsequently described. The socket i0 is tubular, as shown, and a portion thereof extends into the interior of the refector and is formed with slots ll and d2 adapted to receive the anchor pins 43 and 4A. The slot 42 is preferably notched, as indicated at 45, so as to receive the pin 445 the pin 43 being mounted on one side of the lamp case 51 and the two pins i l, and l4? being noun ad on the opposite side. It is apparent tillS construction permits insertion of the p base in only one position, this being one s r; a:

and displaced preferably, though not ly equal distances from the axis of :ector. l hese filaments should be ac- 'ately positioned, one directly above the ier, so as to prevent lateral offsetting of the concentrated portions of the light beam.

The two filament construction is of the tvp-e shown in my copending application,

ial No. 703,846, filed April 3, 1924;, conting in two filaments, one above the other, coiled V-shapcd wire construction, one side of each of said filaments having a common ground base and the other side having rated base contacts 55, adapted to act with yieldable connector rods 56 mounted within socket interior and connecting the electric circuit cords 57 nd On the base 51 of the bulb, as

icroinabove referred. to, the anchor pins and l4: are mounted and these cooperatively engage Lshaped bayonet slots l1 and of the socket.

ll ithin the globe 52 and mounted on the upper filament lead-in wire is a light shield d 331K ably in the shape of a curvilinear sector alufi-Hgli satisfactory loll ment be permitted to escape so as to secure illumination for the vehicle directly in front of the same, this type of radiation not producing appreciable glare.

Preferably also, the rear face of the shield is blackened or otherwise treated to prevent as far as possible, reflection therefrom for a purpose as will be brought out later. The position of the shield in the globe may be varied in its relation to the filament and, in fact in some instances, I may place the shield without the globe, although to secure a diminution of stray reflected light in the bulb, the inner bulb placement is more desirable.

I have provided means for securing a universal adjustment of the filament of the bulb by means of mechanism which will now be described. Attached to the upper surface of the socket connector is a U-shaped plate 60 having upturned arms 61 and 62 suitably apertured and threaded to receive the adjusting rod 63. This rod has threaded engagement with the arms 61 and 62 and extends rearwardly from the arm 62 of the member 60 through the adjusting plate 6e accessible through an aperture 65 in the rear face 11 of the headlamp casing. The head 66 of the adjusting rod 63 is on the rear face of the plate 64 so that it may be manipulated to adjust the headlamp filament. The rod is held in position by means of a cotter pin 67 at its inner end which prevents accidental removal of the threaded bolt63 and by means of a coil spring 68 wound about the screw, one end of the spring contacting against the upstanding arm 62 of the plate 60 and the other end contacting against the inner base of the adjusting plate 64. The spring serves the purpose of tensioning the plate 64: relativeto the head 66 of the adjusting bolt 63 to bring about frictional engagement between said head and plate, and this engagement is augmented by means of oppositely extending ridges 69 formed in plate 6% immediately beneath the head surface of the head 66 of the rod 63 which latter surface is provided with cooperating radiating grooves suitably displaced one from the other so that the adjusting bolt may be held in one of various adjusted positions and yieldably retained from movement due to vibration of the automobile, which tends to cause rotation of the same.

Additional meansis also provided tending to maintain the adjusting rod 63 in its set position, consisting in a resilient plate 70 shown clearly in Figures 1 and 4, which is gagement in the slot 7 2 tending to prevent its rotation and thus cooperating with the holding means for the rod previously described.

The adjusting plate S-lis adapted to be n;

moved to a limited extent vertically, this movement carryingwith it the adjusting rod and thus causing a tipping action of the bulb socket and a vertical displacement of the filaments. The edges of the opening 65 ya the drawing, has a circular central portion 81 and radially extending end plates 82 and 83, these end plates having side portions 84 struck out to form radially extending channels 85 and 86 in which the square nuts 87 and 88 of the plate adjusting bolts 89 and 90 are secured. It should be noted that the radial plates 82 and 83 of the adjusting plate 64: are slotted radially as indicated at 91 and 92 to receive the bolts 89 and 90 and to permit a vertical adjustment of the plate 64 relative to the casing. The bolts 89 and 90 extend through apertures 93 and Se in the casing plate 11 immediately above and below the adjustment aperture 65, the heads 95 and 96 thereof being accordingly accessible from v the exterior of the headlamp casing.

The essential physical characteristics of the invention as shown in'the exemplary embodiment of the drawings having been de scribed, it remains to indicate the cooperative relationship between the various structural elements of the invention and to explain the operation and results obtained by the use of the apparatus. elements of the apparatus may first be described.

The lens 15 is preferably of the type shown in my Patent No. 1,460,834, the operation of the lens being tomodify light beams reflected from the reflector so as to direct them to that portion of the road or passageway which requires the necessary illumination.

The type of lamp bulb employedin the system of lighting described, is that in which two filaments are used, the lamp bulb being prefl erably positioned in the reflector so that one filament is directly above the other and both filaments are equally displaced from the axis of the reflector. WVith this type of bulb, when one, as the upper, filament is lighted, the center of illumination of a light beam in front of the reflector is shifted downwardly relative to-the axis of the reflector, and similarly when the lower filament is lighted the center of intensity of illumination is shifted up The functions of the various Wardly relative to the reflector axis. An additional effect of displacing the center of the light source from the axis of the reflector is that the height of the light beam is magnified over that of the light beam resulting when the filament is exactly at focus. The effect therefore, of the use of a displaced filament is to throw out a light beam which has considerable height in the direction of the car movement and which, since the displacement of the light source is small, has adequate intensity for proper illumination.

In the case where two filaments are used, one below and one above the reflector axis the operator or oriverof the car may use either filament at will and thus obtain control over illumination thrown relatively close to the front of the car by means of the upper filament and illumination relatively further displaced from the car through use of the lower filament. In order to maintain this type of illumination within legal requirements as to the height of the beam, it is of course desirable to give the reflector a permanent tilt reiative to the normal horizontal of the car frame so that the height of the beam from the lower filament does not exceed that required by law and best engineering practice.

The function of the shield 57 is twofold. In the first place, it is adapted to cut off direct rays emerging from the light source and extending in an upward direction above the average height of the light beams from the reflector and constituting what is known as glare. The use of the shield cuts off these upwardly directed rays and consequently diminishes glare.

Another very important function of the shield is to control a type of secondary reflection of the interior of the globe of the lamp bulb which has been found heretofore extremely difficult to prevent. It has been estimated between 5% to 8% of the light from a filament is reflected from the interior of the globe and forms a secondary image, causing considerable stray light radiation and in creasing glare. In the case of the two filament bulb, when one filament is lighted, the

light rays reflected from the interior of the bulb form a secondary image on the other side of the lamp axis which serves as a second source of illumination causing the undesirable effects above noted. Applicant has ascertained that by means of the shield which is appropriately blackened on its rear face or otherwise treated to prevent re-radiation of light, the formation of the second image through reflection from the interior of the globe is very largely prevented, this, of course, resulting in a more efficient and exact control of the light emanation of the bulb and consequent better illumination from the lamp.

The whole functioning of the filaments with the attached shield and the reflector and lens are modified and controlled by the type of adjusting mechanism provided for the lamp bulb. In the present invention, I have utilized very effective means for obtaining not only an axial adjustment of the filament establish this position of the filament initially, but also to maintain the same steadily throughout the use of the automobile.

Two adjustments are utilized in the headlamp of the present invention, the axially adjusting rod 63, with its head 66 and the vertical adjusting bolts 89 and 90 with the adjusting heads 95 and 96, all of which extend to the exterior of the casing 10. As is clearly evident from inspection of Figure 1 of the drawing, rotation of the screw head 66, by appropriate means, causes an axial movement of the socket 40 and 0f the lamp base. By this means therefore, there is axial adjustment of the filament of the lamp secured.

Vertical adjustment of the filament results from a shifting of the adjusting plate 64 this shifting being accomplished by loosening the bolts 89 and 90 by appropriate means and subsequently shifting the plate 64 through manipulation of the head 66. When the plate is in the desired position where the filaments are accurately positioned relative to the axis of the reflector, the bolts 89 and 90 are tightened.

it should be observed that the inturned flange of the casing plate 11 adjacent the aperture 65 and the outturned flange of the adjusting plate 64, each having frictional contact with each other which is greatly augmented by tightening the bolts 89 and 90 so that when the proper vertical adjustment of the filament is had, the adjustment is permanently maintained. Also note should be made of the frictional holding means provided for the adjusting bolt 63 consisting in the coopcrating ridges and grooves 69, and the resilient friction plate 7 0, these two elements combining to resist the tendency of the bolt to work in its thread and thus prevent disturbance of the initial axial setting of the filaments. The action of the spring 36 about the rearwardly extending fingers 35 of the reflector also tends to resist axial movement of the socket 4.0.

Reference should be made further to the anchor pins positioned on opposite sides of the base of the bulb and one of them having a greater diameter than the other, there be ing slots of corresponding width. WVith this construction, it is impossible to insert the bulb in the socket incorrectly.

While I have described in this specification an embodiment of my invention having certain structural details which may be pre ferred, I of course do not desire to be specifically limited to said structure as variations of the same may be made such as come within the scope of the claims hereto appended.

Having thus described my invention, what I desire to secure by United States Letters Patent and claim is:

' 1.. In a lamp construction, the combination of a casing; a reflector within the casing; a socket movably mounted within the aperture formed adjacent the axis of the reflector; an electric bulb mounted within the socket and reflector; and means for transversely adjusting said bulb relative to the reflector, said means comprising a plate mounted internally of the casing and adjacent an aperture formed in said casing; connecting means between the socket and plate; means forholding said plate in transversely adjusted rela tionship to the casing, said socket being adapted to pivot within the reflector with movement of the plate, said last named means including bolts extending through a portion of the plate and the wall of the casing, the head of the bolt protruding on the external side of the casing; a nut threaded on the inner end of said bolt, and means for preventing rotation of said nut; and additional means for assisting in preventing transverse movement of the plate when in adjusting position, said additional means including resilient contacting members intermediate the plate and easing.

2. In a headlamp construction, the combination of a casing; a reflector Within said casing; a bulb socket positioned within an aperture formed adjacent the axis of the reflector and movable therein; a lamp bulb within the reflector and socket; means for axially adjusting the position of the socket and bulb relative tothe reflector, said means including a threaded rod, a portion of which extends to the exterior oi the casing; a threaded plate fixed to the socket; and means for frictionally resisting rotation of the said threaded rod when in a set position, said last named means including a slotted plate mounted on the socket and contacting with said red, the edges of said slot frictionally contacting with the threaded surface of the rod.

3. In a headlamp construction, the combination of a casing; a reflector within said casing; a bulb socket positioned within an aperture formed adjacent the axis of the reflector and movable therein; a lamp bulb within the reflector and socket; means for axially adjusting the position of the socket and bulb relative to the reflector, said means including a threaded rod, a portion of which extends to the exterior of the casing; a threaded plate flxed to the socket; means for frictionally resisting rotation of the said threaded rod when in a set position, said last named means including a plate mounted on the socket and frictionally contacting intermediate its length with said rod; and a yieldable resilient member interposed .be-'

tween the casing in which the rod is mounted on the socket.

4. In a headlamp construction, the combination of a casing; a reflector within said casing; a bulb socket positioned within an aperture formed adjacent the axis ofthe reflector and movable therein; a lamp bulb within the reflector and socket; means for axially adjusting the position of the socket and bulb relative to the reflector, said means including a threaded rod, a portion of which extends to the exterior of the casing; a threaded plate fixed to the socket; means for frictionally resisting rotation of the sait threaded rod when in a set position; and

additional means for frictionally resisting rotation of the rod including a ridge formed on the external portion of the casing adjacent the rod, cooperating grooves formed on the base of the head portion of the rod, and a spring mounted on the rod interior of the casing and adapted to yieldably engage said casing member and a portion of the socket.

5. In a headlamp construction, the combination of a casing; a reflector within the casing; a lens in front of the reflector; a lamp bulb socket mounted within an aperture formed adjacent the axis of the reflector and movable therein; a lamp bulb mounted in said socket and within the reflector; means for adjusting the socket axially in the reflector, said means including a casing member, a rod extending through said casing member to the exterior of the casing and to the interior of the casing adjacent said socket, said rod being threaded, and a cooperating threaded member flxed to the socket; and means for holding said socket in predetermined adjusted position, said means including cooperating ridge and slot portions intermediate the head of the rod and the socket member, a coil spring mounted on the rod intermediate the casing member and a portion of the socket, a resilient plate mounted on the socket and frictionally contacting with said rod, and an annular coil spring mounted on said reflector and contacting with spaced portions of the socket.

6. In a headlamp construction, the combination of a casing having an aperture formed in the rear Wall thereof, said aperture having an inwardly turned flange; a reflector positioned within the casing having an axial aperture formed therein; a lamp bulb socket pivotally and slidably mounted in said aperture; a plate positioned on said casing aperture Within the casing; means for adjustably securing said plate to the casing over said casing aperture; means connecting the plate and the socket for adjusting the socket including a screw threaded bolt; and means including a slotted resilient plate engaging said bolt for resisting rotation thereof, said casing aperture flange forming a resilient frictional holding means for said plate.

In testimony whereof I afiix my signature.

SAMUEL F. ARBUCKLE. 

